biology exam 4
Net number of ATP produced in glycolysis
2 ATP
Describe the three phases of the Calvin cycle
1. Carbon fixation (adding CO2 to RuBP by rubisco): light-independent reactions are initiated; CO2 is fixed from an inorganic to an organic molecule 2. Reduction (of 3-phosphoglycerate to G3P): ATP and NADPH are used to reduce 3-PGA into G3P; then ATP and NADPH are converted to ADP and NADP+ 3. Regeneration (of RuBP): RuBP is regenerated, which enables the system to prepare for more CO2 to be fixed
Recognize the overall chemical equation for photosynthesis
6CO2 + 6H2O → C6H12O6 + 6O2
electron transport chain
A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP.
why is there an energy-investment phase and energy-harvesting phase to glycolysis
ATP is used during the energy-investing phase to power the glycolysis reaction; ATP is produced during the energy-harvesting phase.
Distinguish between the aerobic and anaerobic phases of cellular respiration
Aerobic respiration can only occur in the presence of oxygen. During aerobic respiration, the reactants oxygen and glucose are turned into the products carbon dioxide, water, and ATP Anaerobic occurs when oxygen is not present. it consists of 2 steps. the first is like aerobic and the second is fermentation
what is the role of electron carriers in respiration
An electron carrier is a molecule that transports electrons during cellular respiration. ... The energy stored in NADH + H+ and FADH2 will be released later in cellular respiration to generate ATP, which can be used as an energy source throughout the cell.
Compare and contrast autotrophs and heterotrophs.
Autotrophs and heterotrophs are both living organisms that require some form of food to get energy. But autotrophs make their own food via photosynthesis or some other similar method. Heterotrophs get their food by eating autotrophs or other heterotrophs.
Explain why C4 photosynthesis is advantageous in hot, dry conditions
C4 plants grow better than C3 plants under hot, dry conditions when plants must close their stomata to conserve water
cellular respiration equation
C6H12O6 + 6O2 --> 6CO2 + 6H2O + ATP
Explain the role of NAD+ and FAD in cellular respiration
Cellular respiration produces energy by oxidizing the carbons in glucose. In order to do this most efficiently, the cell oxidizes carbons in a series of small steps, instead of all at once. In some of these steps, electrons are transferred from the carbons in order to oxidize carbon. These electrons are initially moved to either NAD or FAD, reducing them to NADH or FADH2. The reduced NADH or FADH2 transfer these electrons to the electron transport chain, which in a series of steps move the electrons to oxygen, completing the oxidation of glucose.
Explain the similarities, and differences, between cellular respiration and photosynthesis. Use the chemical equation for these reactions in your answer
Cellular respiration takes place in the mitochondria of cells. While photosynthesis requires energy and produces food, cellular respiration breaks down food and releases energy. Plants perform both photosynthesis and respiration, while animals can only perform respiration
what is the role of the mitochondria in cellular respiration
Converts food into ATP (energy for cell), max production of ATP, and comes from mother.
Identify how each stage of the aerobic pathway contributes to the generation of ATP in a cel
During aerobic cellular respiration, glucose reacts with oxygen, forming ATP that can be used by the cell. Carbon dioxide and water are created as byproducts. In cellular respiration, glucose and oxygen react to form ATP. Water and carbon dioxide are released as byproducts
how can ATP continue to be produced in the absence of oxygen
Fermentation. Some organisms are able to continually convert energy without the presence of oxygen. They undergo glycolysis, followed by the anaerobic process of fermentation to make ATP.
Calculate the number of NADH, FADH2, and ATP molecules produced by each stage of cellular respiration per glucose molecule.
Glycolysis (anaerobic), Krebs cycle, oxidative phosphorylation - 36 Glycolysis, fermentation - 2
Describe why the H+ gradient across a thylakoid membrane is referred to as a storage of energy.
High-energy electrons leave the chlorophyll and enter an electron transport chain, which is a series of proteins in the membrane of the thylakoid. ... Their energy is used to pump H+ ions from outside to inside the thylakoid against a concentration gradient. The H+ ions build up inside the thylakoid
Identify the photosynthetic pigments required to absorb the various wavelengths of light necessary for photosynthesis.
In plants, chlorophyll a and chlorophyll b are the main photosynthetic pigments. Chlorophyll molecules absorb blue and red wavelengths, as shown by the peaks in the absorption spectra above.
inputs and outputs of the preparatory reaction
Inputs - 2 NAD+ Outputs - 2 NADH, 2 CO2
What are the inputs and outputs of the ETC
Inputs - ADP + P, NADH + H+, FADH2, Oxygen Outputs - ATP, NAD+, FAD+, H20
disadvantages of fermentation
Lactate and alcohol are toxic to cells. Lactate changes pH and causes muscles to fatigue. Oxygen debt Yeast die from the alcohol they produce by fermentation
Compare the overall chemical equation for photosynthesis and cellular respiration
Notice that the equation for cellular respiration is the direct opposite of photosynthesis: Cellular Respiration: C6H12O6 + 6O2 → 6CO2 + 6H2O. Photosynthesis: 6CO2 + 6H2O → C6H12O6+ 6O
Explain how different photosynthetic modes allow plants to adapt to a particular environment.
Photosynthesis is essential for life on earth, so different organisms adapted to different environments to sustain life.
Explain the role of photosynthesis for all organisms on Earth.
Photosynthesis is important to living organisms because it is the number one source of oxygen in the atmosphere. Without photosynthesis, the carbon cycle could not occur, oxygen-requiring life would not survive and plants would die
Describe the similarities and differences between cellular respiration and photosynthesis
Photosynthesis makes the glucose that is used in cellular respiration to make ATP
Describe the process of photosynthesis in terms of two sets of reactions that take place in a chloroplast.
Photosynthesis takes place in two stages: light-dependent reactions and the Calvin cycle. Light-dependent reactions, which take place in the thylakoid membrane, use light energy to make ATP and NADPH.
Explain why a plant cell must contain both chloroplasts and mitochondria.
Plant cells need both chloroplasts and mitochondria because they perform both photosynthesis and cell respiration
Where does the electron transport chain occur?
inner membrane of mitochondria
Explain the role of the noncyclic electron pathway and the cyclic electron pathway
The functions of cyclic and noncyclic electron flow. Ciclic electron flow = used to compensate for higher ATP requirements. Non-cyclic electron flow = electron energy can be uses to reduce to NADP+ (NADH in cellular respiration)
Contrast the processes of C3, C4, and CAM photosynthesis
The main difference between C3 C4 and CAM photosynthesis is that C3 photosynthesis produces a three-carbon compound via the Calvin cycle, and C4 photosynthesis produces an intermediate four-carbon compound, which split into a three-carbon compound for the Calvin cycle, whereas CAM photosynthesis gathers sunlight
Identify which part of a thylakoid will contain the photosystems, electron transport chain, and the ATP synthase complex
The photosynthetic electron transport complexes in the thylakoid membrane include phycobilisome (the membrane associated antenna complex), photosystem II (PSII), photosystem I (PSI), cytochrome (cyt) b6f and ATP synthase (ATPase).
the relationship between the metabolic pathways within the mitochondria and glycolysis
The two main metabolic pathways, i.e glycolysis and oxidative phosphorylation are linked by the enzyme complex pyruvate dehydrogenase. Briefly, glucose is transported inside the cell and oxidized to pyruvate. ... These reduced equivalents are oxidized further by the mitochondrial respiratory chain
Describe how carbon dioxide is fixed and then reduced to a carbohydrate
This process is called carbon fixation, because CO2 is "fixed" from its inorganic form into organic molecules
Describe the organization of the thylakoid and how this organization is critical to the production of ATP during photosynthesis.
Thylakoids are usually arranged in stacks (grana) and contain the photosynthetic pigment (chlorophyll). The grana are connected to other stacks by simple membranes (lamellae) within the stroma, the fluid proteinaceous portion containing the enzymes essential for the photosynthetic dark reaction, or Calvin cycl
Explain how the products of the Calvin cycle are used to form the other molecules found in plants
Using the energy carriers formed in the first stage of photosynthesis, the Calvin cycle reactions fix CO2 from the environment to build carbohydrate molecules.
how does fermentation act as a NAD+ recycling system.
When oxygen is not present, pyruvate will undergo a process called fermentation. In the process of fermentation the NADH + H+ from glycolysis will be recycled back to NAD+ so that glycolysis can continue
why is there variation in the number of ATP molecules produced per glucose
While glucose catabolism always produces energy, the amount of energy (in terms of ATP equivalents) produced can vary, especially across different species. The number of hydrogen ions the electron transport chain complexes can pump through the membrane varies between species
inputs and outputs of the citric acid cycle
inputs are 2 Acetyl CoA and water reactants are 6 NADH, 2 FADH, 4 CO2, 2 ATP
environmental conditions that would cause a muscle cell to undergo fermentation.
anaerobic conditions
Identify various plants that use a method of photosynthesis other than C3 photosynthesis
c4
Why do leaves appear green?
chlorophyll reflects and transmits green light
citric acid cycle
completes the breakdown of glucose
Where does glycolysis occur?
cytoplasm
cellular respiration
is the process in which organisms break down glucose from food to create a usable form on energy called ATP
Glycosis
first step in releasing the energy of glucose, in which a molecule of glucose is broken into two molecules of pyruvic acid
Inputs of Glycolysis
glucose, 2 ATP, 2 NAD+
Phases of Cellular Respiration
glycolysis, preparatory reaction, citric acid cycle, electron transport chain
Where does the preparatory reaction occur?
matrix
Where does the citric acid cycle occur?
mitochondrial matrix
Compare the production of NADPH to ATP in noncyclic photosynthesis
oncyclic photophosphorylation involves both Photosystem I and Photosystem II and produces ATP and NADPH.
preparatory reaction
produces molecule that enters citric acid cycle in the matrix of the mitochondria
Advantages of fermentation
provides a quick burst of ATP energy for muscular activity
Outputs of Glycolysis
pyruvate, ATP, and NADH
Illustrate why it takes three turns of the Calvin cycle to produce one glucose molecule.
the initial product of photosynthesis? Because G3P has three carbon atoms, and each turn of the cycle takes in one carbon atom in the form of carbon dioxide.
why is ATP both an input and output of glycolysis
to provide energy so glycolysis can occur
